Seam tape and methods of manufacture and use thereof

ABSTRACT

Provided herein are seam tapes and related methods. The seam tapes can be compatible with polyolefin-based waterproof/breathable (w/b) membranes, including polypropylene (PP) w/b membranes and/or polyethylene (PE) w/b membranes. Also provided are seams sealed by means of these seam tapes, as well as materials, fabrics, and garments including one or more of these sealed seams.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 15/724,359, filed Oct. 4, 2017, which claims the benefit of U.S.patent application Ser. No. 14/665,296 filed Mar. 23, 2015, now U.S.Pat. No. 9,790,337, issued on Oct. 17, 2017, which claims the benefit ofU.S. Provisional Application No. 61/968,602 filed Mar. 21, 2014, both ofwhich are hereby incorporated herein by reference in their entirety.

FIELD OF THE APPLICATION

In accordance with at least selected embodiments, this application isdirected to new or improved seam tapes, products made with seam tapes,methods of manufacture and/or methods of use of seam tapes. Inaccordance with at least certain embodiments, exemplary seam tapes maybe compatible with polyolefin-based waterproof/breathable membranes,including polypropylene membranes and/or polyethylene membranes, and/orseams sealed by means of these seam tapes, as well as, materials,fabrics, and/or garments including one or more of the sealed seams.

BACKGROUND

At least certain polyolefin (PO) microporous membranes and microporousfibers (or materials made therefrom) are known to be waterproof (or atleast water resistant) and air permeable due to their chemicalcomposition and structure. Examples of such polyolefin (PO) microporousmembranes and hollow fibers or hollow fiber membranes known to bewaterproof (or water resistant) and air permeable are various CELGARD®membranes, by way of example only, CELGARD® Z-series membranes, orCELGARD® hollow fibers or hollow fiber membranes produced by Celgard,LLC of Charlotte, N.C.

When constructing a waterproof and breathable garment(waterproof/breathable or w/b), seams typically are taped to preventleakage through holes made during stitching. Commercially available seamtapes are generally made from polyurethane (PU), and can be used withwaterproof/breathable (w/b) membranes made from PU, polyester (PET)and/or Teflon (ePTFE). However, these existing seam tapes may not becompatible with polyolefin-based w/b membranes, including polypropylene(PP) w/b membranes and/or polyethylene (PE) w/b membranes.

SUMMARY

Provided herein are seam tapes. The seam tapes can be compatible withpolyolefin-based w/b membranes, including polypropylene (PP) w/bmembranes and/or polyethylene (PE) w/b membranes. The seam tapes cancomprise a microporous polyolefin film made by a dry-stretch process andincluding a plurality of pores. In some cases, the plurality of porescan have a substantially round shape. In some cases, the microporouspolyolefin film can exhibit a ratio of machine direction tensilestrength to transverse direction tensile strength of from 0.5 to 5.0. Insome cases, the microporous polyolefin film has a JIS Gurley of 100seconds or less (e.g., a JIS Gurley of 80 seconds or less).

The melting temperature of the polyolefin can be selected so as toprovide a seam tape that (i) can be applied to w/b membranes withoutdamaging the w/b material, and (ii) does not melt at the temperaturesencountered during everyday use. For example, the polyolefin can have amelt temperature of from 80° C. to 175° C. In some embodiments, thepolyolefin can have a melt temperature of from 80° C. to 120° C. (e.g.,from 90° C. to 110° C., from 95° C. to 105° C., or from 99° C. to 100°C.). In other embodiments, the polyolefin can have a melt temperature offrom 155° C. to 175° C. (e.g., from 165° C. to 175° C.).

The microporous polyolefin film can be formed from any suitablepolyolefin material. In some embodiments, the polyolefin comprisespolypropylene, polyethylene, or a combination thereof (e.g., blendsthereof and/or copolymers thereof). In some cases, the polyolefin cancomprise impact copolymer polypropylene. In some cases, the polyolefincan comprise a polypropylene polyethylene block copolymer. In somecases, the polyolefin can comprise metallocene polyethylene.

In one example, the polyolefin can comprise a polypropylene polyethyleneblock copolymer having a melt temperature of from 155° C. to 175° C.(e.g., from 165° C. to 175° C.). In one example, the polyolefin cancomprise metallocene polyethylene having a melt temperature of from 80°C. to 120° C. (e.g., from 90° C. to 110° C., from 95° C. to 105° C., orfrom 99° C. to 100° C.).

In some embodiments, the microporous polyolefin film can be a biaxiallyoriented microporous polyolefin film. In some embodiments, themicroporous polyolefin film can have a thickness of from 8 microns to 80microns. In some embodiments, the microporous polyolefin film can have aTD tensile strength of at least 175 kg/cm² (e.g., a TD tensile strengthof at least 225 kg/cm²). In some embodiments, the microporous polyolefinfilm can have a TD shrinkage of less than 6.0% at 90° C. and less than15.0% at 120° C.

The microporous polyolefin film can have a porosity of from 20% to 90%(e.g., a porosity of from 20% to 80%, a porosity of from 40% to 90%, ora porosity of from 65% to 90%). In some embodiments, the plurality ofpores in the microporous polyolefin film can have an average pore sizeof from 0.03 microns to 0.50 microns and an aspect ratio of from 0.75 to1.25. In some cases, the microporous polyolefin film can have a meanflow pore diameter of at least 0.04 microns (e.g., a mean flow porediameter of at least 0.05 microns). In some cases, the microporouspolyolefin film can have an Aquapore size of at least 0.06 microns(e.g., at least 0.08 microns).

In some embodiments, the microporous polyolefin film can comprise amulti-ply microporous polyolefin film (e.g., a bi-layer polymer film atri-layer polymer film, or a polymer film comprising more than threelayers). Optionally, in some embodiments, the microporous polyolefinfilm can further comprise a nonwoven material (e.g., a spunbond and/ormeltblown nonwoven material), a woven material, a knit material, or acombination thereof disposed on a side of the microporous polyolefinfilm. In these embodiments, the microporous polyolefin film and thenonwoven material, woven material, and/or knit material can be combinedthrough any suitable process, such as adhesive or thermal lamination,embossing, calendering, or combinations thereof. In some embodiments,the microporous polyolefin film can further comprise an adhesivedisposed on the microporous polyolefin film.

As described above, the seam tapes provided herein can be used to sealthe seams of waterproof fabrics, including polyolefin-based waterprooffabrics. Accordingly, also provided are seams sealed by means of theseam tapes described herein. The seams can comprise a first edge ofwaterproof fabric (e.g., polyolefin-based waterproof fabric, such as aPP w/b membrane and/or PE w/b membrane) sewn together to a second edgeof waterproof fabric (e.g., polyolefin-based waterproof fabric, such asa PP w/b membrane and/or PE w/b membrane) along a stitch line; and aseam tape described herein adhered to the first edge of waterprooffabric and the second edge of waterproof fabric and covering the stitchline. In some embodiments, the seam can further comprise an adhesivebonding the seam tape to the first edge of waterproof fabric and thesecond edge of waterproof fabric. In some embodiments, the seam can besubstantially free of adhesives. Also provided are materials, fabrics,and garments comprising one or more of the seams described above, aswell as methods of making materials, fabrics, and garments using theseam tapes described herein.

DETAILED DESCRIPTION

Provided herein are seam tapes. The seam tapes can be compatible withpolyolefin-based w/b membranes, including polypropylene (PP) w/bmembranes and/or polyethylene (PE) w/b membranes. The seam tapes cancomprise a microporous polyolefin film made by a dry-stretch process andincluding a plurality of pores.

Suitable microporous polyolefin film may include polyolefin microporousmembranes made by dry-stretch processes, such as those described in U.S.Pat. No. 6,602,593 as well as those described in U.S. Patent ApplicationPublication Nos. 2007/0196638, 2008/0118827, 2011/0223486, and2014/0302374, all of which are hereby incorporated by reference.

In some cases, the microporous polyolefin film can be auniaxially-oriented polyolefin Celgard membrane, such as those describedin U.S. Pat. No. 6,602,593. In other cases, the microporous polyolefinfilm can be a biaxially-oriented polyolefin Celgard membrane, such asthose disclosed in U.S. Patent Application Publication Nos. 2007/0196638and 2011/0223486. Such biaxially-oriented membranes may, in someinstances, perform better as seam tapes than uniaxially-oriented Celgardmembranes. Moreover, biaxially-oriented Celgard membranes made fromblock copolymers of polyethylene and polypropylene may have anadditional advantage of exceptionally pleasant touch or hand. However,uniaxially-oriented microporous membranes can also be used.

In one embodiment, the seam tape can include a microporous polyolefinfilm made by a dry-stretch process. The microporous polyolefin film caninclude a plurality of pores. In some instances, the pores can becharacterized as substantially round shaped. In some embodiments, theplurality of pores in the microporous polyolefin film can have anaverage pore size, as measured by scanning electron microscopy (SEM) offrom 0.03 microns to 0.50 microns. Further, the pore shape can becharacterized by an aspect ratio, the ratio of the length to the widthof the pore. In some embodiments, the aspect ratio of the pores, asmeasured by SEM, can range from 0.75 to 1.25 (e.g., from 0.85 to 1.15).

The melting temperature of the polyolefin can be selected so as toprovide a seam tape that (i) can be applied to w/b membranes withoutdamaging the w/b material, and (ii) does not melt at the temperaturesencountered during everyday use. For example, in some embodiments, thepolyolefin can have a melt temperature of at least 80° C. (e.g., atleast 85° C., at least 90° C., at least 95° C., at least 100° C., atleast 105° C., at least 110° C., at least 115° C., at least 120° C., atleast 125° C., at least 130° C., at least 135° C., at least 140° C., atleast 145° C., at least 150° C., at least 155° C., at least 160° C., atleast 165° C., or at least 170° C.). In some embodiments, the polyolefincan have a melt temperature of 175° C. or less (e.g., 170° C. or less,165° C. or less, 160° C. or less, 155° C. or less, 150° C. or less, 145°C. or less, 140° C. or less, 135° C. or less, 130° C. or less, 125° C.or less, 120° C. or less, 115° C. or less, 110° C. or less, 105° C. orless, 100° C. or less, 95° C. or less, 90° C. or less, or 85° C. orless).

The polyolefin can have a melt temperature ranging from any of theminimum values described above to any of the maximum values describedabove. For example, in some embodiments, the polyolefin can have a melttemperature of from 80° C. to 175° C. (e.g., from 80° C. to 120° C.,from 90° C. to 110° C., from 95° C. to 105° C., from 155° C. to 175° C.,or from 165° C. to 175° C.). In one embodiment, the polyolefin can havea melt temperature of from 99° C. to 100° C.

The microporous polyolefin film can be formed from any suitablepolyolefin material. For example, the microporous polyolefin film can beformed from polypropylene, polyethylene, poly 1-butene, poly(4-methyl-1pentene), polyhexene, polyoctene, blends thereof, and copolymersthereof. In certain embodiments, the polyolefin can comprisepolypropylene, polyethylene, or a combination thereof (e.g., blendsthereof and/or copolymers thereof).

In some embodiments, the polyolefin can be selected from the groupconsisting of polypropylene homopolymers (e.g., atactic polypropylene,isotactic polypropylene, and syndiotactic polypropylene), polypropylenecopolymers (e.g., polypropylene random copolymers), polypropylene impactcopolymers, polyethylene, polyethylene copolymers, polybutylene,poly(4-methyl-1-pentene), and mixtures thereof. Suitable polypropylenecopolymers include, but are not limited to, random copolymers made fromthe polymerization of propylene in the presence of a comonomer selectedfrom the group consisting of ethylene, but-1-ene (i.e., 1-butene), andhex-1-ene (i.e., 1-hexene). In such polypropylene random copolymers, thecomonomer can be present in any suitable amount (e.g., an amount of lessthan 10 wt. %, such as from 1 to 7 wt. %).

In some embodiments, the polyolefin can comprise a polyolefin blockcopolymer. For example, in some cases, the polyolefin can comprise apolypropylene polyethylene block copolymer. PP/PE block copolymers areavailable from various resin manufacturers. By using a block copolymerthat includes at least a small percentage of PE (preferably less than5%), the resulting film is less stiff, thus giving a softer drape andquieter movement, and also has a lower coefficient of friction, thusgiving a silkier touch. Also, such block copolymer films appear to besuitable for TD stretching and for fabricating 60 inch wide (or wider)films for textile applications. In some embodiments, the polyolefin cancomprise a low-melting point olefin block polymer, such as octene-PEblock copolymer sold by Dow Chemical under the trade name INFUSE.

In certain embodiments, the polyolefin can comprise an impact copolymerpolypropylene. Suitable polypropylene impact copolymers include, but arenot limited to, those produced by the addition of a copolymer selectedfrom the group consisting of ethylene-propylene rubber (EPR),ethylenepropylene-diene monomer (EPDM), polyethylene, and plastomers toa polypropylene homopolymer or polypropylene random copolymer. In suchpolypropylene impact copolymers, the copolymer can be present in anysuitable amount, but typically is present in an amount of from about 5to about 25 wt. %.

In some embodiments, the thermoplastic polymer can be a polyethylene.Suitable polyethylenes include, but are not limited to, low densitypolyethylene, linear low density polyethylene, medium densitypolyethylene, high density polyethylene, and combinations thereof. Incertain embodiments, the thermoplastic polymer can be selected from thegroup consisting of medium density polyethylene, high densitypolyethylene, and mixtures thereof. In certain embodiments, thethermoplastic polymer can be a high density polyethylene.

In some embodiments, the polyolefin can comprise a low-melting pointolefin polymer, such as a metallocene-catalyzed polyolefin. Examples ofsuitable metallocene-catalyzed polyolefins include metallocenepolyethylenes and metallocene polyethylene copolymers. A metallocene isa compound typically consisting of two cyclopentadienyl anions (Cp,which is C₅H₅—) bound to a metal center (M) in the oxidation state II,with the resulting general formula (C₅H₅)₂M. Closely related to themetallocenes are the metallocene derivatives (e.g., titanocenedichloride, vanadocene dichloride). Certain metallocenes and theirderivatives exhibit catalytic properties. Cationic group 4 metallocenederivatives related to [Cp₂ZrCH₃]⁺ can catalyze olefin polymerization.Examples of suitable metallocene polyethylenes (mPE) include mPEs soldunder the trade name ENABLE™ by Exxon. In the case of seam tapes formedfrom mPEs, the seam tape may work exceptionally well as a seam tape forfabrics made with PO, PP, and/or PE w/b membranes. Metallocene PE filmscan have exceptionally good hand (they are soft, pliable, and elastic)and, in addition, they can have a melt temperature of about 99° C. or100° C.

In one example, the polyolefin can comprise a polypropylene polyethyleneblock copolymer having a melt temperature of from 155° C. to 175° C.(e.g., from 165° C. to 175° C.). In one example, the polyolefin cancomprise metallocene polyethylene having a melt temperature of from 80°C. to 120° C. (e.g., from 90° C. to 110° C., from 95° C. to 105° C., orfrom 99° C. to 100° C.).

When the microporous polyolefin film is formed from the variousmaterials described above, by way of example, from a polyolefin combinedwith one or more block or impact copolymers, the microporous polyolefinfilm can be used to form microporous membranes, materials, layers,composites, laminates, or textiles with targeted, enhanced performanceproperties in or for textile related end use applications. Tailoring thechoice of composition, in the chemical structure of the polymeric blendor composition of the modified composition, membrane or fiber, ormaterial, layer, composite, laminate, or textile made therewith ortherefrom can influence performance properties such as hand, drape,“quietness” with movement, and surface coefficient of friction therebyproducing microporous polyolefin membranes, fibers, microporous fibers,or materials, layers, composites, laminates, or textiles with betterhand, softer drape, quieter movement, and/or lower coefficient offriction resulting in, for example, a silkier touch.

In other select embodiments, the microporous polyolefin film can furtherinclude other ingredients. For example, the microporous polyolefin filmcan further include fillers (e.g., inert particulates used to reduce thecost of the film, but otherwise having no significant impact on themanufacture of the membrane or its physical properties), anti-staticagents, anti-blocking agents, anti-oxidants, lubricants (e.g., tofacilitate manufacture), and the like.

In other embodiments, various materials may be added to the polyolefinto modify or enhance the properties of resulting membranes. Suchmaterials include, but are not limited to: (1) mineral fillersincluding, but not limited to, calcium carbonate, zinc oxide,diatomaceous earth, talc, kaolin, synthetic silica, mica, clay, boronnitride, silicon dioxide, titanium dioxide, barium sulfate, aluminumhydroxide, magnesium hydroxide and the like, and blends thereof; (2)elastomers including, but not limited to, ethylene-propylene (EPR),ethylene-propylene-diene (EPDM), styrene-butadiene (SBR), styreneisoprene (SIR), ethylidene norbornene (ENB), epoxy, and polyurethane andblends thereof; (3) wetting agents including, but not limited to,ethoxylated alcohols, primary polymeric carboxylic acids, glycols (e.g.,polypropylene glycol and polyethylene glycols), functionalizedpolyolefins, etc.; (4) lubricants, for example, silicone,fluoropolymers, Kemamide®, oleamide, stearamide, erucamide, calciumstearate, or other metallic stearate; (5) flame retardants for example,brominated flame retardants, ammonium phosphate, ammonium hydroxide,alumina trihydrate, and phosphate ester; (6) cross-linking or couplingagents; (7) polymer processing aid; and (8) any type of nucleatingagents including beta-nucleating agent for polypropylene. In oneexample, the polyolefin can comprise a polypropylene based impactcopolymer with 90-97% polypropylene content compounded with abeta-nucleating (BN) agent.

In certain embodiments, microporous polyolefin film can comprise 1) oneor more block or impact copolymers (BCPs or ICPs) or 2) a polyolefin incombination with one or more BCPs or ICPs. These olefin materials canprovide for a range of differentiated textile materials having improvedperformance properties such as more desirable hand, drape and surfacecoefficient of friction for use in a variety of textile end useapplications which may also require waterproof and breathabilityperformance, such as outerwear, disposable garments, durable garments,textile materials requiring relative humidity equalization, and garmentsor items in medical related applications.

In some cases, the microporous polyolefin film can have a JIS Gurley of100 seconds or less (e.g., 95 seconds or less, 90 seconds or less, 85seconds or less, 80 seconds or less, 75 seconds or less, 70 seconds orless, 65 seconds or less, 60 seconds or less, 55 seconds or less, 50seconds or less, 45 seconds or less, 40 seconds or less, 35 seconds orless, 30 seconds or less, 25 seconds or less, 20 seconds or less, or 15seconds or less). In some embodiments, the microporous polyolefin filmcan have a JIS Gurley of at least 10 seconds (e.g., at least 15 seconds,at least 20 seconds, at least 25 seconds, at least 30 seconds, at least35 seconds, at least 40 seconds, at least 45 seconds, at least 50seconds, at least 55 seconds, at least 60 seconds, at least 65 seconds,at least 70 seconds, at least 75 seconds, at least 80 seconds, at least85 seconds, at least 90 seconds, or at least 95 seconds.

The microporous polyolefin film can have a JIS Gurley ranging from anyof the minimum values described above to any of the maximum valuesdescribed above. For example, the microporous polyolefin film can have aJIS Gurley of from 10 seconds to 100 seconds (e.g., from 10 seconds to75 seconds).

In some embodiments, the microporous polyolefin film can have athickness of at least 8 microns (e.g., a thickness of at least 10microns, a thickness of at least 15 microns, a thickness of at least 20microns, a thickness of at least 25 microns, a thickness of at least 30microns, a thickness of at least 35 microns, a thickness of at least 40microns, a thickness of at least 45 microns, a thickness of at least 50microns, a thickness of at least 55 microns, a thickness of at least 60microns, a thickness of at least 65 microns, a thickness of at least 70microns, a thickness of at least 75 microns, a thickness of at least 80microns, a thickness of at least 85 microns, a thickness of at least 90microns, or a thickness of at least 95 microns). In some embodiments,the microporous polyolefin film can have a thickness of 100 microns orless (e.g., 95 microns or less, 90 microns or less, 85 microns or less,80 microns or less, 75 microns or less, 70 microns or less, 65 micronsor less, 60 microns or less, 55 microns or less, 50 microns or less, 45microns or less, 40 microns or less, 35 microns or less, 30 microns orless, 25 microns or less, 20 microns or less, 15 microns or less, or 10microns or less.

The microporous polyolefin film can have a thickness ranging from any ofthe minimum values described above to any of the maximum valuesdescribed above. For example, the microporous polyolefin film can have athickness of from 8 microns to 100 microns (e.g., from 10 microns to 100microns, from 8 microns to 80 microns, or from 25 microns to 75microns). In one example, the microporous polyolefin film can have athickness of from 38 microns to 50 microns.

In some embodiments, the microporous polyolefin film can have a MDtensile strength of at least 200 kg/cm² (e.g., at least 250 kg/cm², atleast 300 kg/cm², at least 350 kg/cm², at least 400 kg/cm², at least 450kg/cm², at least 500 kg/cm², at least 550 kg/cm², at least 600 kg/cm²,at least 650 kg/cm², at least 700 kg/cm², at least 750 kg/cm², at least800 kg/cm², at least 850 kg/cm², at least 900 kg/cm², at least 950kg/cm², at least 1000 kg/cm², at least 1100 kg/cm², at least 1200kg/cm², at least 1300 kg/cm², or at least 1400 kg/cm²). In someembodiments, the microporous polyolefin film can have a MD tensilestrength of 1500 kg/cm² or less (e.g., 1400 kg/cm² or less, 1300 kg/cm²or less, 1200 kg/cm² or less, 1100 kg/cm² or less, 1000 kg/cm² or less,950 kg/cm² or less, 900 kg/cm² or less, 850 kg/cm² or less, 800 kg/cm²or less, 750 kg/cm² or less, 700 kg/cm² or less, 650 kg/cm² or less, 600kg/cm² or less, 550 kg/cm² or less, 500 kg/cm² or less, 450 kg/cm² orless, 400 kg/cm² or less, 350 kg/cm² or less, 300 kg/cm² or less, or 250kg/cm² or less).

The microporous polyolefin film can have a MD tensile strength rangingfrom any of the minimum values described above to any of the maximumvalues described above. For example, the microporous polyolefin film canhave a MD tensile strength of from 200 kg/cm² to 1500 kg/cm² (e.g., from600 kg/cm² to 1500 kg/cm²).

In some embodiments, the microporous polyolefin film can have a TDtensile strength of at least 175 kg/cm² (e.g., at least 200 kg/cm², atleast 225 kg/cm², at least 250 kg/cm², at least 275 kg/cm², at least 300kg/cm², at least 350 kg/cm², at least 400 kg/cm², at least 500 kg/cm²,at least 600 kg/cm², at least 700 kg/cm², at least 800 kg/cm², at least900 kg/cm², or at least 1000 kg/cm²). In some embodiments, themicroporous polyolefin film can have a TD tensile strength of 1100kg/cm² or less (e.g., 1000 kg/cm² or less, 900 kg/cm² or less, 800kg/cm² or less, 700 kg/cm² or less, 600 kg/cm² or less, 500 kg/cm² orless, 400 kg/cm² or less, 350 kg/cm² or less, 300 kg/cm² or less, 275kg/cm² or less, 250 kg/cm² or less, 225 kg/cm² or less, or 200 kg/cm² orless).

The microporous polyolefin film can have a TD tensile strength rangingfrom any of the minimum values described above to any of the maximumvalues described above. For example, the microporous polyolefin film canhave a TD tensile strength of from 175 kg/cm² to 1100 kg/cm².

In some embodiments, the ratio of MD tensile strength to TD tensilestrength can be at least 0.5 (e.g., at least 1.0, at least 2.0, at least3.0, at least 4.0, or at least 5.0). In some embodiments, the ratio ofMD tensile strength to TD tensile strength can be 6.0 or less (e.g., 5.0or less, 4.0 or less, 3.0 or less, 2.0 or less, or 1.0 or less.

The ratio of MD tensile strength to TD tensile strength can range fromany of the minimum values described above to any of the maximum valuesdescribed above. For example, the microporous polyolefin film canexhibit a ratio of MD tensile strength to TD tensile strength of from0.5 to 6.0 (e.g., from 0.5 to 5.0, or from 0.5 to 4.0).

In certain embodiments, the microporous polyolefin film can have a TDshrinkage of less than 6.0% at 90° C. and less than 15.0% at 120° C.

In some embodiments, the microporous polyolefin film can have a porosityof at least 20% (e.g., at least 40%, at least 50%, at least 65%, or atleast 80%). In some embodiments, the microporous polyolefin film canhave a porosity of 90% or less (e.g., 80% or less, 65% or less, 50% orless, or 40% or less).

The microporous polyolefin film can have a porosity ranging from any ofthe minimum values described above to any of the maximum valuesdescribed above. For example, the microporous polyolefin film can have aporosity of from 20% to 90% (e.g., a porosity of from 20% to 80%, aporosity of from 40% to 90%, or a porosity of from 65% to 90%).

In some embodiments, the microporous polyolefin film can have a meanflow pore diameter (measured with Capillary Flow analysis using the ASTMF316-86 standard method) of at least 0.04 microns (e.g., a mean flowpore diameter of at least 0.05 microns).

In some embodiments, the microporous polyolefin film can have anAquapore size (measured using the Aquapore available through PMI (PorousMaterials Inc.)) of at least 0.06 microns (e.g., at least 0.08 microns).

In some embodiments, the microporous polyolefin film can have ahydrohead pressure (measured using the ASTM D3393-91 standard method) ofgreater than about 140 psi.

In one embodiment, the microporous polyolefin film can be a mPE filmwith a thickness of about 54.4 microns, a basis weight of about 48.6microns, a puncture strength of about 410 grams, an MD tensile strengthof about 438 kg/cm², a percent elongation at break in the MD of about759%, a TD tensile strength of about 248 kg/cm², and a percentelongation at break in the TD of about 817%.

In one embodiment, the microporous polyolefin film can be a mPE filmwith a thickness of about 97 microns, a basis weight of about 88.9microns, a puncture strength of about 678 grams, an MD tensile strengthof about 371 kg/cm², a percent elongation at break in the MD of about815%, a TD tensile strength of about 352 kg/cm², and a percentelongation at break in the TD of about 999%.

The microporous polyolefin film can comprise a single-ply microporouspolyolefin film or a multi-ply microporous polyolefin film (e.g., abilayer film, a trilayer film, a quad-layer film, etc.). Multi-ply filmscan be prepared using standard lamination methods known in the art.Multi-ply films can be prepared using co-extrusion methods known in theart. Multi-ply films can be made of plies of the same materials or ofdiffering materials. In certain embodiments, the microporous polyolefinfilm can comprise a multi-ply comprising at least three layers (e.g., atleast four layers, at least five layers, at least six layers, or atleast seven layers). In some cases, the microporous polyolefin film cancomprise a multi-ply comprising from three to eight layers (e.g., fromthree to six layers). In one embodiment, the microporous polyolefin filmcan comprise a polypropylene-polyethylene-polypropylene trilayer film.

In one example embodiment, the microporous polyolefin film can compriseCelgard® microporous membranes, particularly a Z-Series membrane.

Optionally, in some embodiments, the seam tape can further comprise anonwoven material (e.g., a spunbond and/or meltblown nonwoven material),a woven material, or a knit material disposed on a side of themicroporous polyolefin film. The nonwoven can be, for example, apolypropylene nonwoven. In these embodiments, the microporous polyolefinfilm and the nonwoven, woven, and/or knit material can be combinedthrough any suitable process, such as adhesive or thermal lamination,embossing, calendering, or combinations thereof.

Optionally, in some embodiments, the seam tape can further comprise anadhesive. The adhesive can be, for example, a polymer adhesive. Suitableadhesives are known in the art, and can be selected based on theiradhesion properties, hydrophobicity or hydrophilicity, melting point,shear resistance, bonding/coating properties, washing and dry cleaningtemperature resistance, cleaning solvent resistance, high temperatureresistance (e.g., ability to withstand autoclaving) chemical resistance,gas resistance, resistance to pathogens such as viruses and bacteria, aswell as ability to commingle with the laminated fabrics or theircomponents so as to create a hydrostatically sealed seam or a seam thatis resistant to chemical and/or biological agents. The seam tape wouldalso be designed to be stretchable to match the stretch characteristicsof the face fabric and inner liner laminates. Suitable adhesive polymerresins include, but are not limited to, polyurethanes, polypropylenes,polyam ides, polyesters, and polyolefins.

In some embodiments, the seam tape can include a base material, and anadhesive applied to one side of the base material. The base material caninclude any materials or methods of manufacture disclosed herein. In oneembodiment, the base material can include a microporous polyolefin film.In other select embodiments, the base material can include a monolithicfilm. Yet in other select embodiments, the base material can includeboth microporous polyolefin films and monolithic films in combination.The base material can be provided with any desired thickness for theseam tape. In some select embodiments, the base material can include asingle layer to produce the desired thickness. In other selectembodiments, the base material can be made from multiple layers toproduce the desired thickness of the seam tape. The tape or tape basematerial could be 1-ply (monolayer), 2-ply (bi-layer), 3-ply(tri-layer), 4-ply (quad-layer)-membranes, or any number of layersrequired to produce the desired final seam tape thickness.

The seam tapes described herein can be of various shapes and sizes. Insome embodiments, the seam tape is 0.5 inches or greater in length(e.g., 1 inch or greater, 2 inches or greater, 3 inches or greater, 4inches or greater, 5 inches or greater, 6 inches or greater, 7 inches orgreater, 8 inches or greater, 9 inches or greater, 10 inches or greater,15 inches or greater, 20 inches or greater, 25 inches or greater, 30inches or greater, 35 inches or greater). In some embodiments, the seamtapes are 150 inches in length or less (e.g., 100 inches or less, 50inches or less, 40 inches or less, 30 inches or less, 20 inches or less,10 inches or less, 5 inches or less, 2 inches or less).

In some embodiments, the seam tape is 0.25 inches or greater in width(e.g., 0.3 inches or greater, 0.4 inches or greater, 0.5 inches orgreater, 0.75 inches or greater, 1 inch or greater, 1.25 inches orgreater). In some embodiments, the seam tape is 3 inches or less inwidth (e.g., 2 inches or less, 1.5 inches or less, 1 inch or less, 0.75inches or less, 0.5 inches or less, 0.35 inches or less). In certainembodiments, the seam tape can be 15 mm, 16, mm, 17 mm, 18 mm, 19 mm, 20mm, 21 mm, 22 mm, 23 mm, or 24 mm in width. In certain embodiments, theseam tape can be from 18 mm to 20 mm in width.

In some embodiments, the seam tape is rectangular. In some embodiments,the seam tape is elliptical. In some embodiments, the seam tape iscircular. The seam tape can be cut in any shape or pattern. The seamtape can be curved or arced.

The seam tape can be provided as a set of seam tapes forming adjoiningstrips of a sheet of seam tapes. Individual pieces of seam tape can beseparated by lines of perforations. The seam tape can be provided as acontinuous roll. In certain embodiments, the seam tape is provided as acontinuous roll having a length, for example, of 25 m, 50 m, 75 m, or100 m.

The seam tapes described herein can be made by preparing suitablemicroporous polyolefin films using conventional methods.

In some cases, methods can comprise forming a microporous polyolefinfilm by a dry-stretch process. By way of example, in some embodiments,the microporous polyolefin film can be manufactured by a dry-stretchprocess where a polyolefin resin is extruded by blown film technique orby cast film method to form a nonporous precursor which is then cold andhot stretched in the machine direction (uniaxially) to form amicroporous membrane with a final thickness typically less than 75 μm(e.g., from about 25-75 μm (but may be thinner or thicker depending onthe end use)). In some cases, the polyolefin resin can be one or moreblock copolymers (BCPs) or impact copolymers (ICPs), which can eachcomprise polypropylene and/or polyethylene. Alternatively, thepolyolefin resin can be extruded by blown film technique or by cast filmmethod to form a nonporous precursor which is then cold and/or hotstretched in both the machine and transverse directions (biaxially) toform a microporous membrane seam tape with a final thickness typicallyless than 75 μm, preferably from about 25-75 μm.

In some cases, the microporous polyolefin film can be manufactured by adry-stretch process where a polyolefin resin is extruded by blown filmtechnique or by cast film method to form a nonporous precursor which isthen biaxially stretched (i.e., not only stretched in the machinedirection, but also in the transverse machine direction). This processis discussed in great detail in U.S. Patent Application Publication Nos.2007/0196638 and 2011/0223486, which are incorporated herein byreference, and discussed further below.

In general, the process for making the microporous polyolefin film mayinclude the steps of extruding a nonporous precursor, and then biaxiallystretching the nonporous precursor. Optionally, the nonporous precursormay be annealed prior to stretching. Optionally, the nonporous precursorcan be stretched in the machine direction prior to biaxial stretching.In one embodiment, the biaxial stretching includes a machine directionstretch and a transverse direction with a simultaneous controlledmachine direction relax. The machine direction stretch and thetransverse direction stretch can be simultaneous or sequential. In oneembodiment, the machine direction stretch is followed by the transversedirection stretch with the simultaneous machine direction relax. Thisprocess is discussed in greater detail below.

Extrusion can be generally conventional (conventional refers toconventional for a dry-stretch process). The extruder can have a slotdie (for flat precursor) or an annular die (for parison precursor). Inthe case of the latter, an inflated parison technique can be employed(e.g., a blow up ratio (BUR)). However, the birefringence of thenonporous precursor may not have to be as high as in the conventionaldry-stretch process. For example, in the conventional dry-stretchprocess to produce a membrane with a >35% porosity from a polypropyleneresin, the birefringence of the precursor may, in some cases,be >0.0130; while with the instant process, the birefringence of the PPprecursor could be as low as 0.0100. In another example, a membrane witha >35% porosity from a polyethylene resin, the birefringence of theprecursor may, in some instances, be >0.0280; while with the instantprocess, the birefringence of the PE precursor could be as low as0.0240.

In some embodiments, the nonporous precursor can be one of a blown filmand a slot die film. The nonporous precursor can be a single layerprecursor formed by at least one of single layer extrusion andmultilayer extrusion, or a multilayer precursor formed by at least oneof coextrusion and lamination

Annealing (optional) can be carried out, in one embodiment, attemperatures between T_(m)-80° C. and T_(m)-10° C. (where T_(m) is themelt temperature of the polymer); and in another embodiment, attemperatures between T_(m)-50° C. and T_(m)-15° C. Some materials (e.g.,those with high crystallinity after extrusion, such as polybutene) mayrequire no annealing.

Machine direction stretch can be conducted as a cold stretch or a hotstretch or both, and as a single step or multiple steps. In oneembodiment, cold stretching may be carried out at <T_(m)-50° C., and inanother embodiment, at <T_(m)-80° C. In one embodiment, hot stretchingcan be carried out at <T_(m)-10° C. In one embodiment, total machinedirection stretching may be in the range of 50-500%, and in anotherembodiment, in the range of 100-300%. During machine direction stretch,the precursor can shrink in the transverse direction (conventional).

Transverse direction stretching can include a simultaneous controlledmachine direction relax. This means that as the precursor is stretchedin the transverse direction the precursor is simultaneously allowed tocontract (i.e., relax), in a controlled manner, in the machinedirection. The transverse direction stretching can be conducted as acold step, or a hot step, or a combination of both. In one embodiment,total transverse direction stretching can be in the range of 100-1200%,and in another embodiment, in the range of 200-900%. In one embodiment,the controlled machine direction relax can range from 5-80%, and inanother embodiment, in the range of 15-65%. In one embodiment,transverse stretching can be carried out in multiple steps. Duringtransverse direction stretching, the precursor may or may not be allowedto shrink in the machine direction. In an embodiment of a multi-steptransverse direction stretching, the first transverse direction step caninclude a transverse stretch with the controlled machine relax, followedby simultaneous transverse and machine direction stretching, andfollowed by transverse direction relax and no machine direction stretchor relax.

Optionally, the precursor, after machine direction and transversedirection stretching can be subjected to a heat setting, as is wellknown.

In some embodiments, the dry-stretch process can include the steps of:machine direction stretching followed by said biaxial stretchingincluding said transverse direction stretching with simultaneouscontrolled machine direction relax, a second transverse directionstretching with simultaneous machine direction stretching, followed byoptional transverse direction relax.

In some embodiments, the biaxial stretching step of the dry-stretchprocess includes the simultaneous biaxial stretching of a plurality ofseparate, superimposed, layers or plies of nonporous precursor, whereinnone of the plies are bonded together during the stretching process.

In some embodiments, the biaxial stretching step of the dry-stretchprocess includes the simultaneous biaxial stretching of a plurality ofbonded, superimposed, layers or plies of nonporous precursor, whereinall of the plies are bonded together during the stretching process.

In some embodiments, one or more impact copolymers comprisingpolypropylene and polyethylene can be extruded by a blown film techniqueor by a cast film method to form a nonporous precursor film which isthen cold and hot stretched initially in the machine direction (MD) andsequentially stretched in the transverse direction (TD) to form abiaxially stretched or biaxially oriented (BO) microporous membraneaccording to the method described in U.S. Patent Application PublicationNo. 2011/0223486, where the biaxial stretch step includes simultaneousmachine direction relax.

In some embodiments, one or more impact copolymers comprisingpolypropylene and polyethylene can be extruded by a blown film techniqueor by a cast film method to form a nonporous precursor film which isthen cold and hot stretched initially in the machine direction andsequentially stretched in the transverse direction to form a biaxiallystretched or biaxially oriented (BO) microporous membrane according tothe method described in US2011/0223486 where the biaxial stretch stepdoes not include simultaneous machine direction relax.

In some embodiments, a primarily polypropylene (PP)-based blockcopolymer (BCP) with 90-97% polypropylene content can be compounded witha beta-nucleating (BN) agent and extruded, using a cast method, to forma nonporous beta-nucleated polypropylene based BCP precursor. Biaxialstretching of the beta nucleated polypropylene precursor may fracturethe interfaces which exist between regions of beta nucleated PP andregions of alpha nucleated of PP. The fracturing process may form poresin the beta-nucleated biaxially oriented polypropylene (BN-BOPP)membrane producing a microporous membrane with a thickness of less than75 microns (e.g., from about 12 microns to 25 microns).

In some embodiments, the microporous polyolefin film can comprise apolyolefin (PO) in combination with one or more block or impactcopolymers (BCPs or ICPs). In these embodiments, the polyolefin combinedwith one or more impact or block copolymers can be extruded by a blownfilm technique or by a cast film method to form a nonporous precursorwhich is then cold and hot stretched in the machine direction(uniaxially) to form a microporous membrane or film.

In some embodiments, the microporous polyolefin film can comprise a POin combination with one or more ICPs. In these embodiments, the PO incombination with the one or more ICPs can be extruded by a blown filmtechnique or by a cast film method to form a nonporous precursor whichis then cold and hot stretched in the machine direction (MD) andsequentially stretched in the transverse direction (TD) to form abiaxially stretched or biaxially oriented (BO) microporous membraneaccording to the stretch method described in U.S. Patent ApplicationPublication No. 2011/0223486. The transverse stretching step includes asimultaneous machine direction relax step to produce a biaxiallyoriented (BO) microporous membrane.

In some embodiments, the microporous polyolefin film can comprise a POin combination with one or more ICPs. In these embodiments, the PO incombination with the one or more ICPs can be extruded by a blown filmtechnique or by a cast film method to form a nonporous precursor whichis then cold and hot stretched in the machine direction and sequentiallystretched in the transverse direction to form a biaxially stretched orbiaxially oriented (BO) microporous membrane according to the methoddescribed in U.S. Patent Application Publication No. 2011/0223486. Thetransverse stretching step does not include a simultaneous machinedirection relax step to produce a biaxially oriented (BO) microporousmembrane.

In some embodiments, the microporous polyolefin film can comprise a POin combination with one or more ICPs, where the ICP is primarily apolypropylene (PP) based ICP with a 90-97% PP content. In theseembodiments, methods can comprise compounding the ICP with abeta-nucleating (BN) agent, and extruding the ICP using a cast method toform a nonporous beta nucleated PO/ICP precursor. Biaxial stretching ofthe beta nucleated polypropylene precursor may fracture the interfaceswhich exist between regions of beta nucleated PP and regions of alphanucleated PP. The fracturing process may form pores in thebeta-nucleated biaxially oriented polypropylene (BN-BOPP) membraneproducing a microporous membrane with a thickness of less than 75microns (e.g., from about 12 microns to 25 microns).

Certain microporous polyolefin films are highly hydrophobic andexceptionally breathable, which makes them ideal as the barrier layer inwaterproof/breathable textiles such as high-performance outerwear.Traditionally, in the development of such polyolefin films, raw materialpolymers have been selected, among other factors, with a view towardproviding physically robust films. This has resulted in stiffer filmsthat tend to crinkle, thus providing less than ideal “hand” (i.e.,tactile experience). In the case of the seam tapes described herein, themicroporous polyolefin films can be fabricated to exhibit improved hand.One method for improving the hand of such PO films is to use apolypropylene/polyethylene block copolymer resin.

In accordance with one example, the seam tape can comprise a microporouspolyolefin membrane laminated to a porous polymer nonwoven material ormesh, such as a polyolefin nonwoven mesh. Optionally, the assembly canbe microcreped.

In some embodiments, the seam tape can be further improved, treated ormodified using a technique or treatment such as a coating ormicrocreping to introduce permanent small, regularly spaced, crepes,profiles, compactions, pleats, or wrinkles into the laminated orcomposite microporous polyolefin film for the purpose of improvingmechanical strength, elasticity and/or resiliency. In addition, themicrocreped seam tapes can exhibit improved “hand” or softness, improved“next-to-the-skin” softness, and/or improved “quietness” (e.g., lack ofcrinkling noises during movement), which may be desired performanceproperties or characteristics of or in textile garments, materials orapplications.

As described above, the seam tapes provided herein can be used to sealthe seams of waterproof fabrics, including polyolefin-based waterprooffabrics. Although the seam tape described herein can work well withpolypropylene based w/b materials or textiles, the seam tapes can alsobe used with other w/b membranes and films, including, but not limitedto, polyurethane, PTFE, polyester, polyethylene, polypropylene,polyethylene-polypropylene blends, polyolefin copolymers, wet process,dry process, or BNBOPP process porous membranes, the like, and/or othersimilar films, substrates or membranes, or combinations thereof. Forexample, a PP membrane can be seamed or joined to a PE membrane.

Accordingly, also provided are seams sealed by means of the seam tapesdescribed herein. The seams can comprise a first edge of waterprooffabric (e.g., polyolefin-based waterproof fabric, such as a PP w/bmembrane and/or PE w/b membrane) sewn together to a second edge ofwaterproof fabric (e.g., polyolefin-based waterproof fabric, such as aPP w/b membrane and/or PE w/b membrane) along a stitch line; and a seamtape described herein adhered to the first edge of waterproof fabric andthe second edge of waterproof fabric and covering the stitch line.

In some embodiments, the seam can further comprise an adhesive bondingthe seam tape to the first edge of waterproof fabric and the second edgeof waterproof fabric. In some embodiments, the seam can be substantiallyfree of adhesives.

Also provided are materials, fabrics, and garments comprising one ormore of the seams described above, as well as methods of makingmaterials, fabrics, and garments using the seam tapes described herein.Methods of making materials, fabrics, and garments can comprise joininga first edge of waterproof fabric to a second edge of waterproof fabric.These methods can comprise sewing together a first edge of waterprooffabric to a second edge of waterproof fabric to form a stitch line;applying a seam tape described herein to cover the stitch line, andadhering the seam tape to the first edge of waterproof fabric and thesecond edge of waterproof fabric. Adhering the seam tape to the firstedge of waterproof fabric and the second edge of waterproof fabric cancomprise heating the seam tape to a temperature above the melttemperature of the microporous polyolefin film. Adhering the seam tapeto the first edge of waterproof fabric and the second edge of waterprooffabric can comprise heating the seam tape to a temperature above themelt temperature of a polymer adhesive present on the seam tape.

In accordance with at least selected embodiments, this application isdirected to seam tapes, products made with seam tapes, methods ofmanufacture and/or methods of use of seam tapes. In accordance with atleast certain embodiments, exemplary seam tapes may be compatible withpolyolefin-based waterproof/breathable (w/b) membranes, includingpolypropylene (PP) w/b membranes and/or polyethylene (PE) w/b membranes,and/or seams sealed by means of these seam tapes, as well as, materials,fabrics, and/or garments including one or more of the sealed seams.

By way of non-limiting illustration, examples of certain embodiments ofthe present disclosure are given below.

EXAMPLES

All materials were characterized using the following methods unlessotherwise stated. The thickness of membranes was measured with an Emvecomodel 210-A microgage bench micrometer according to the method describedin ASTM D374-99 (2004) entitled “Standard Test Methods for Thickness ofSolid Electrical Insulation,” which is incorporated herein by referencein its entirety. Gurley, as used herein, refers to the JapaneseIndustrial Standard (JIS Gurley), and was measured using the OHKENpermeability tester. JIS Gurley is defined as the time in secondsrequired for 100 cc of air to pass through one square inch of film at aconstant pressure of 4.9 inches of water. Basis weight refers to theweight per unit sample area of a material, and can be expressed ingrams/meter squared. Basis weight was determining the mass (in grams) ofa test sample having a known area (in m²). % Shrinkage was measured byincubating a sample in an oven at 90° C. for 1 hour. Shrinkage was thenmeasured in the MD and/or the TD. Puncture Strength is measured usingInstron Model 4442 tensile tester according to the method described inASTM D3763-14 entitled “Standard Test Method for High Speed PunctureProperties of Plastics Using Load and Displacement Sensors,” which isincorporated herein by reference in its entirety. The measurements weremade across the width of the microporous membrane and the puncturestrength was as the force required to puncture the test sample. Thetensile strength of membranes (both MD and TD) was measured with anInstron Model 4201 tensile tester according to the method described inASTM D882-12 (2012) entitled “Standard Test Method for TensileProperties of Thin Plastic Sheeting,” which is incorporated herein byreference in its entirety. % MD elongation at break refers to thepercentage of extension of a test sample along the MD of the test samplemeasured at the maximum tensile strength needed to break the sample. %TD elongation at break refers to the percentage of extension of a testsample along the TD of the test sample measured at the maximum tensilestrength needed to break a sample. The porosity of membranes wasmeasured according to the method described in ASTM D2873-94 (1999)entitled “Standard Test Method for Interior Porosity of Poly(VinylChloride) (PVC) Resins by Mercury Intrusion Porosimetry,” which isincorporated herein by reference in its entirety.

The membranes described in the following examples were produced byconventional dry-stretched techniques, except as noted.

Example 1

An impact copolymer polyolefin resin was melt extruded to from anonporous precursor membrane 25 microns in thickness. The nonporousprecursor membrane was then stretched uniaxially in the machinedirection (MD) to produce a microporous film that was 20.8 microns inthickness and had a JIS Gurley value=1,354 seconds. The physicalproperties of this membrane are summarized in Table 1 below.

Example 2

The uniaxially stretched microporous membrane prepared in Example 1 wassubsequently biaxially stretched using a transverse direction (TD)stretching device without machine direction (MD) relax. The TD stretchedmembrane was stretched in the TD direction 2 to 4 times its input width.The resulting microporous membrane had a JIS Gurley of <100 seconds,which is an acceptable level of air permeability to function as abreathable textile membrane seam tape.

Example 3

The uniaxially stretched microporous membrane prepared in Example 1 wassubsequently biaxially stretched in the transverse direction (TD) with asimultaneous MD relax step as described in U.S. Patent ApplicationPublication No. 2011/0223486. TD stretching at 4.5× stretch and a 0-16%overall MD relax produced a microporous membrane with a thickness of10.9 microns and a JIS Gurley value of 73 seconds. The physicalproperties of this membrane are summarized in Table 1 below.

Example 4

An impact copolymer polyolefin resin was melt extruded to form anonporous precursor membrane 35 microns in thickness. The nonporousprecursor membrane was then stretched uniaxially in the machinedirection (MD) to produce a microporous film that was 26 microns inthickness and had a JIS Gurley value of 3,454 seconds. The physicalproperties of this membrane are summarized in Table 1 below.

Example 5

The uniaxially stretched microporous membrane prepared in Example 4 wassubsequently biaxially stretched in the transverse direction (TD) with asimultaneous MD relax step as described in U.S. Patent ApplicationPublication No. 2011/0223486. TD stretching at 4.5× stretch and a 0-16%overall MD relax produced a microporous membrane with a thickness of 19microns and a JIS Gurley value of 25 seconds. The physical properties ofthis membrane are summarized in Table 1 below.

TABLE 1 Summary of the physical properties of the membranes prepared inExamples 1 and 3-5. Membrane Exam- Exam- Exam- Exam- ple 1 ple 3 ple 4ple 5 Thickness (microns) 20.8 10.9 26 19 JIS Gurley (sec) 1,354 733,454 25 Basis Weight (g/m²) 10.4 2.6 15.5 4.0 % MD shrinkage (90° C., 1hour) 12.1 6.6 0.6 5.7 % TD shrinkage (90° C., 1 hour) — 0.87 4.2Puncture Strength (g) — 69.9 124 MD tensile strength (kg/cm²) 1,538397.6 1,612 561.0 TD tensile strength (kg/cm²) 163.8 393.3 194 266.3 %MD elongation at break 52.4 67.9 78.2 120.5 % TD elongation at break651.9 43.1 685.8 58.8

Example 6

A polypropylene (PP)-based impact copolymer was extruded to form a film.The extruder melt temperature was 249° C. The polymer melt was fed to anextrusion die set at 215° C. The polymer melt was cooled by blowing air.The extruded film had a thickness of 34 microns and birefringence of0.0116.

The extruded precursor was then annealed at 154° C. for 2 minutes. Theannealed film was then cold stretched to 30% at room temperature, andthen hot stretched 190% and relaxed 61% at 140° C. (total MDstretch=159%). The MD stretched film had a thickness of 26 microns andporosity of 40%. The MD stretched film was then TD stretched 260% at150° C. with 50% MD relax, followed by a simultaneous MD and TD stretchof 50% and 216%, respectively, at 150° C.

The physical properties of this membrane are summarized in Table 2below. For purposes of comparison, the physical properties of twosamples of commercially available dry-stretched films: (A) CELGARD® 2400(a single ply polypropylene membrane); and (B) CELGARD® 2325 (atri-layer polypropylene/polyethylene/polypropylene membrane).

TABLE 2 Summary of the physical properties of the membrane prepared inExamples 6. A B Example 6 Thickness (microns) 25.4 25.1 17 Porosity 37%40%  73% TD Tensile Strength (kg/cm²) 160 146 287 MD Tensile Strength(kg/cm²) 1,700 1,925 558 MD/TD Tensile Strength Ratio 10.6 13.2 1.9 TDStretching — — 450%

The compositions and methods of the appended claims are not limited inscope by the specific compositions and methods described herein, whichare intended as illustrations of a few aspects of the claims. Anycompositions and methods that are functionally equivalent are intendedto fall within the scope of the claims. Various modifications of thecompositions and methods in addition to those shown and described hereinare intended to fall within the scope of the appended claims. Further,while only certain representative compositions and method stepsdisclosed herein are specifically described, other combinations of thecompositions and method steps also are intended to fall within the scopeof the appended claims, even if not specifically recited. Thus, acombination of steps, elements, components, or constituents may beexplicitly mentioned herein or less, however, other combinations ofsteps, elements, components, and constituents are included, even thoughnot explicitly stated.

The term “comprising” and variations thereof as used herein is usedsynonymously with the term “including” and variations thereof and areopen, non-limiting terms. Although the terms “comprising” and“including” have been used herein to describe various embodiments, theterms “consisting essentially of” and “consisting of” can be used inplace of “comprising” and “including” to provide for more specificembodiments of the invention and are also disclosed. Other than wherenoted, all numbers expressing geometries, dimensions, and so forth usedin the specification and claims are to be understood at the very least,and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, to be construed in light of thenumber of significant digits and ordinary rounding approaches.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of skill in the artto which the disclosed invention belongs. Publications cited herein andthe materials for which they are cited are specifically incorporated byreference.

What is claimed is:
 1. A seam tape adapted to prevent water leakagethrough holes made by a needle in a seam during stitching, comprising: amicroporous, dry-stretched, polyolefin film including a plurality ofpores, wherein the microporous, dry-stretched, polyolefin film comprisesa polymer selected from the group consisting of impact copolymerpolypropylenes, metallocene polyethylenes, and polypropylenepolyethylene block copolymers; an adhesive disposed on one side of themicroporous, dry-stretched, polyolefin film; and wherein themicroporous, dry-stretched, polyolefin film has a porosity of from 20%to 80%.
 2. The seam tape of claim 1, wherein the plurality of pores havea substantially round shape.
 3. The seam tape of claim 1, wherein theplurality of pores have an average pore size of from 0.03 microns to0.50 microns.
 4. The seam tape of claim 1, wherein the microporous,dry-stretched, polyolefin film has a TD tensile strength of at least 175kg/cm².
 5. The seam tape of claim 1, wherein the microporous,dry-stretched, polyolefin film exhibits a ratio of machine directiontensile strength to transverse direction tensile strength of from 0.5 to5.0.
 6. The seam tape of claim 1, wherein the plurality of pores have anaspect ratio of 0.75 to 1.25.
 7. The seam tape of claim 1, wherein themicroporous, dry-stretched, polyolefin film has a melt temperature offrom 80° C. to 175° C.
 8. The seam tape of claim 7, wherein themicroporous, dry-stretched polyolefin film has a melt temperature offrom 80° C. to 120° C.
 9. The seam tape of claim 7, wherein themicroporous, dry-stretched polyolefin film has a melt temperature offrom 155° C. to 175° C.
 10. The seam tape of claim 1, wherein themicroporous, dry-stretched polyolefin film comprises impact copolymerpolypropylene.
 11. The seam tape of claim 1, wherein the microporous,dry-stretched polyolefin film comprises a polypropylene polyethyleneblock copolymer.
 12. The seam tape of claim 1, wherein the microporous,dry-stretched, polyolefin film comprises metallocene polyethylene. 13.The seam tape of claim 1, wherein the microporous, dry-stretched,polyolefin film has a TD tensile strength of at least 225 kg/cm². 14.The seam tape of claim 1, wherein the microporous, dry-stretched,polyolefin film has a thickness of from 8 microns to 80 microns.
 15. Theseam tape of claim 1, wherein the microporous, dry-stretched, polyolefinfilm has a TD shrinkage of less than 6.0% at 90° C. and less than 15.0%at 120° C.
 16. The seam tape of claim 1, wherein the microporous,dry-stretched, polyolefin film comprises a multi-ply microporous polymerfilm.
 17. The seam tape of claim 1, further comprising a nonwovenmaterial, a woven material, a knit material, or a combination thereofdisposed on a side of the microporous, dry-stretched, polyolefin film.18. The seam tape of claim 1, wherein the microporous, dry-stretched,polyolefin film is a biaxially oriented microporous polyolefin film. 19.A seam comprising the seam tape of claim 1, the seam tape preventingleakage through holes made in the seam during stitching.
 20. A seamcomprising a first edge of waterproof fabric sewn together to a secondedge of waterproof fabric along a stitch line; and the seam tape ofclaim 1 adhered to the first edge of waterproof fabric and the secondedge of waterproof fabric and covering the stitch line.
 21. The seam ofclaim 19, further comprising an adhesive bonding the seam tape to thefirst edge of waterproof fabric and the second edge of waterprooffabric.
 22. A seam tape comprising: a microporous, dry-stretched,polyolefin film including a plurality of pores, wherein the microporous,dry-stretched, polyolefin film has a JIS Gurley of 100 seconds or less;and an adhesive disposed on one side of the microporous, dry-stretched,polyolefin film, and wherein the microporous, dry-stretched, polyolefinfilm has a porosity of from 40% to 90%, a JIS Gurley of less than 100, amean flow pore diameter of at least 0.04 microns, and an Aquapore sizeof at least 0.06 microns.
 23. A seam tape adapted to prevent waterleakage through holes made by a needle in a seam during stitching,comprising: a microporous, dry-stretched, polyolefin film including aplurality of pores having a substantially round shape, wherein themicroporous, dry-stretched, polyolefin film has a melt temperature from80° C. to 175° C.; and an adhesive disposed on one side of themicroporous, dry-stretched, polyolefin film, wherein the adhesivecomprises one or more polyolefins; and wherein the plurality of poreshave an average pore size of from 0.03 microns to 0.50 microns; andwherein the microporous, dry-stretched, polyolefin film has a porosityof from 20% to 80% and a TD tensile strength of at least 175 kg/cm². 24.The seam tape of claim 23, wherein the microporous, dry-stretched,polyolefin film exhibits a ratio of machine direction tensile strengthto transverse direction tensile strength of from 0.5 to 5.0.
 25. Theseam tape of claim 23, wherein the plurality of pores have an aspectratio of from 0.75 to 1.25.
 26. The seam tape of claim 23, wherein themicroporous, dry-stretched, polyolefin film has a melt temperature offrom 80° C. to less than 150° C.
 27. The seam tape of claim 23, whereinthe microporous, dry-stretched, polyolefin film has a melt temperatureof from 80° C. to 120° C.
 28. The seam tape of claim 23, wherein themicroporous, dry-stretched, polyolefin film has a melt temperature offrom 155° C. to 175° C.
 29. The seam tape of claim 23, wherein themicroporous, dry-stretched, polyolefin film comprises polypropylene,polyethylene, or a combination thereof.
 30. The seam tape of claim 26,wherein the microporous, dry-stretched, polyolefin film comprises impactcopolymer polypropylene.
 31. The seam tape of claim 26, wherein themicroporous, dry-stretched, polyolefin film comprises a polypropylenepolyethylene block copolymer.
 32. The seam tape of claim 26, wherein themicroporous, dry-stretched, polyolefin film comprises metallocenepolyethylene.
 33. The seam tape of claim 23, wherein the microporous,dry-stretched, polyolefin film has a porosity of from 40% to 90%, a JISGurley of less than 100, a mean flow pore diameter of at least 0.04microns, and an Aquapore size of at least 0.06 microns.
 34. The seamtape of claim 23, wherein the microporous, dry-stretched, polyolefinfilm has a TD tensile strength of at least 225 kg/cm².
 35. The seam tapeof claim 23, wherein the microporous, dry-stretched, polyolefin film hasa thickness of from 8 microns to 80 microns.
 36. The seam tape of claim23 wherein the microporous, dry-stretched, polyolefin film has a TDshrinkage of less than 6.0% at 90° C. and less than 15.0% at 120° C. 37.The seam tape of claim 23, wherein the microporous, dry-stretched,polyolefin film comprises a multi-ply microporous polymer film.
 38. Theseam tape of claim 23, further comprising a nonwoven material, a wovenmaterial, a knit material, or a combination thereof disposed on a sideof the microporous, dry-stretched, polyolefin film.
 39. The seam tape ofclaim 23, wherein the microporous, dry-stretched, polyolefin film is abiaxially oriented microporous polyolefin film.